Control mechanism



April23, 1946. v. F. ZAHODlAKlN 2,393,375

CONTROL MECHANISM Filed March 4, 1942 2 Sheets-Sheet 2 27a: 7a V I N V EN TOR.

Wcroe [Z4 Hoom rrm/ 5 ATTORNEYS Patented Apr. 23, 1946 UNITED STATES PATENT OFFICE CONTROL MECHANISM Victor F. Zahodiakin, Short Hills, N. J.

Application March 4, 1942, Serial No. 433,363

4 Claims.

My invention relates to control mechanism of the type comprising a cam and an associated cam follower.

My invention, in on important aspect thereof, relates to mechanism of the character described wherein thecam is operated by a shaft which is longitudinally movable in opposite directions in order to be connected or disconnected to or from a source of power.

My invention, in another important aspect thereof, relates to mechanism as described wherein the cam follower is controlled by oppositely acting springs, one of which tends to maintain the cam follower in friction-free relation with respect to the associated longitudinally movable cam shaft. 7

My invention has further reference to a novel arrangement for holding a cam in a desired position circumferentially of its supporting shaft.

Various other objects, advantages and features of my invention will become apparent from the following detailed description.

My invention resides in the control mechanism, cam and cam follower mechanism, features and combinations of the character hereinafter described and claimed.

For an. understanding of my invention and for an illustration of one of the forms thereof, reference is to be had to the accompanying drawings, in which:

Figure 1 is a vertical sectional view, partly in elevation, showing the control mechanism of my invention;

Fig. 2 is a transverse, vertical sectional view, partly in elevation, taken on the line 22 ofFig. 1 looking in the direction of the arrows;

Fig. 3 is an elevational view illustrating a part of my novel mechanism; and

Fig. 4 is a perspective view of a cam follower.

In one of its important aspects, my invention relates to a control mechanism utilizable for synchronizing with an aircraft propeller the firing operation of a machine gun, a gun of other desired type, or other suitable projecting device, such guns or projecting device being hereinafter generically termed a machine gun. In a more general aspect, my invention relates to control mechanism comprising an actuating cam and. an actuated cam follower which delivers energy impulses to any selected member or equivalent having any desired control, indicating or other operative function.

Referring to Figs. 1 and 2, I have illustrated a housing I which defines an interior chamber 2, the housing I, in the vertical side wall thereof toward the left, Fig. I, being provided with a circular opening 3 which communicates with said ,chamber 2.

In alinement with the opening 3, a headorcap 4 is secured exteriorly to saidvertical side wall by bolts 9a, Fig.2, and this head 4 is provided with a central passage in which i disposed a sleeve 5 fixed to the head A in suitable manner. The sleeve isupports a shaft 6 which terminatesin an inner threaded section 9a and of said shaft 6 and a flangedsection 5a of the sleeve 5. With an arrangement of the character described, the clutch disk 1 is secured to the shaft 6 for rotatable movement therewith as a unit. U The vertical sidewall of the housing l toward the right, 'Fig. L-is provided with a circular opening .8which is horizontally alined with the aforesaid housing opening 3. A solenoid or elecfro-magnetic pole structure 9 formed from suitable magnetic material issecured exteriorlyto said lastnamed side wall in alinement with the opening 8 by the; aforesaid bolts 9a. The pole structure 9 is provided centrally thereof with a passage which extends horizontally therethrough and which is lined with abushing I0 formed from suitable non-magnetic material such, for example, as brass, bronze or the like. l

The pole structure 9 isprovided with a longitudinally extending section 9?) of reduceddiameter to which a sleeve l l is suitably secured, asby a press-fitting operation. The sleeve H has a solenoid coil or winding I! wound or disposed thereon in other suitable manner, this coil being enclosed by electricity-insulating members I20: as shown. The end of the sleeve II is closed by a cylindrical insert l3 secured in position .by a press-fitting operation or in other suitable manner, the insert i3 carrying a plug I4 formed from suitable electricity-insulating material. The winding I 2 is housed by a cylindrical shell l5 which, at one end, rests upon the pole structure 9. The ends of the sleeve I l and shell I 5 toward the right, Fig. l, terminate in the same vertical plane whereas the adjacent end of the winding l2 terminates short of this plane. The resulting space is filled by a ring |'6 Whl0h, preferably, is welded to the aforesaid sleeve H as indicated at 19a. The flange of a threaded nozzle I1 is held flatwise against the ring l9 and adjacent surfaces by said ring l5.

As shown in Fig. 1, one terminal I8 of the winding l2 extends through the sleeve H and the insert H! in electricity-insulated relation with respect thereto and said terminal I8 is connected to a terminal member it which is embedded in and supported by the plug 5. The other terminal of the winding i2 may be grounded onto the housing from which an electrical connection be taken as indicated at 20, Fig. 1.

The above described clutch disk 1 comprises a hub la which is disposed in horizontal alinement with the aforesaid bushing I3.

2| adapted for both rotatable and longitudinal may The hub la; and the bushing 0 form bearings for a cam shaft I movement thereon. As shown in Fig. 3;;one end of the cam shaft 2| faces the clutch disk! and these facing surfaces are notchedin such manner that they assume a clutching relation with respect to each other when they are engaged as illustrated in Fig. 1.

The end of the cam shaft 2| toward the'right,

Fig. 1, is secured for longitudinal movement with a solenoid core member 22 disposed in a chamber formed by a part of the aforesaid sleeve ll. As shown, an anti-friction thrust bearing'23 should be associated with the adjacent end of the cam shaft 2| and the core member 22.

The end of the cam shaft 2| towardthe left,

Fig. 1, is so shaped thatit'forms a longitudinally extending chamber 2|a into which extends the aforesaid hub la of the clutch disk T so as to form the above described bearing for: the cam shaft 2|. The reduced section 6b f the shaft 6 also extends into the chamber 2|a,,and car ries an anti-friction thrust bearing 24 between which and the opposite wall of the'chamber 2-|a is confined a spiral spring 25 inherently tending to bias the cam shaft 2| from left to right, Fig. 1.

In accordance with the invention, the cam shaft 2! comprisesa circular section 2|b on which a clutch ring 26 and the hub 21a ofa cam 21 are mounted. Opposite faces of the clutch ring 26 are serrated as indicated in Fig. 3. One set of these serrations cooperatesiwith similar serrations formed on the faceof a flange 2|c of the cam shaft 2 I. The other set of these serrations cooperates with similar serrations formed on the adjacent face of the cam hub 21a.

The cam shaft 2| comprises a threaded section 2|d with which a nut member 28 is associated, this nut member 28, when threaded toits limit toward the left, Fig. l, coacting with the cam hub 27a to hold the latter together with the clutch rality of pairs of alined notches formed at the outer edge of said nut member 28.

The hereinbef ore described housing I has formed therein lower and upper passages 30 and 3| which are disposed in vertical alinement. The

lower passage 30 has a sleeve 32 seated therein and the lower open end of this sleeve 32 is closed by a cap member 33, the sleeve and cap member being secured to the housing I by suitable means as shown in Fig. 2.

The vertical passage defined by the sleeve 32 a plurality of screws Fa which are threaded into receives, in freely slidable and non-rotatable relation, the non-circular base 34a, Fig. 4, of a cam follower 34, said base 34a supporting a horizontally journalled pin 35 carrying a cam roller 36 with which the cam 2'! is coactable in the manner hereinafter described.

The cam follower 34 comprises an intermediate section formed with an el1iptica1 opening 34b or equivalent, Fig. 4, through which extends the aforesaid cam sh'aft 2|, the opening 34b being of such size-and shape as to prevent mechanical interference between said cam shaft 2 the cam hub together with the clutch ring 25 on the one hand and the cam follower 34 on the other hand during reciprocation of the latter. The cam follower 34 further comprises an upper section 3&0 freely slidable in the upper pasthe cam follower section 34d. One end of the spring 48 seats against the member 31 and the other end thereof seats against a washer 4| coactable with a flanged surface 366 of the cam follower section 340, said washer 4| being adapted toseat on a flanged surface la of the housing I.

With an arrangement of this character, the spring ii) constantly biases the cam follower 34 in a downward direction as indicated in Fig. l.

The member 31 is exteriorly threaded as indicated at 31a for the attachment thereto of a casing 42 for a cable 53 connected to the upper end of the cam follower 34 and which leads to a suitable trigger motor 44, for example, as known in the art of firing machine guns and comprising a helical spring 45 which tends to draw the cam follower 34 in an upward direction, Fig. 1.

As will be understood from a consideration of Fig. l, the springs 48' and 45 oppose each other as regards action thereof on the camfo-llower 34. That is, the spring 45 tends to draw said cam follower upwardly and the spring 40 tends to push the same downwardly.

' In accordance with the invention, the force of the spring 4|] as applied to the cam follower 34 should be somewhat greater than the opposing force applied thereto including the force applied by the spring 45. The force differences between these two springs may vary within rather wide limits. .l-Iowever, for purposes of explanation of the invention, it may be assumed that the spring 45 applies an upward force, for example, of pounds to the cam follower 34 and that the spring 43 applies a downward force, for example, of pounds to said cam follower 34. Under these circumstances, the spring 40 moves and holds the cam follower 34 downwardly, as shown in Fig. l, to the limit permitted by the housing flange la. However, as will be obvious, further downward movement of thecam follower 34 beyond this limit is resisted by the full force of the spring 45.

In accordance with the invention, the hereinbefore described shaft 6 has connected thereto a shaft, not shown, which is rotated by theaircraft engine. After installation on an aircraft of a device of the character described, the shaft 5 should be operatively connected to the aircraft engine as described above and the cable 113 should be connected to the trigger motor 44. Therethe clutch face at the end thereof from theclutchi upon, with the aircraft engine non-operative, the aircraft propeller is moved manually to the position which it is to occupy when abulletfrom the machine gun is to be fired between the propeller blades, such movement of the aircraft pro-.

'peller being accompanied, of course, by movement of the engine pistons, crankshaft and the herein described shaft 6. As hereinafter described, the bullet is fired when the high section of the cam 21 moves the cam follower 34 downwardly, Fig. .1, against the action of the trigger motor'spring 45.

After the aircraft propeller has been moved to the position described above, the aforesaid bolts 9a which retain the pole structure 9 on the housing l are retracted whereupon the entire solenoid structure is removed as a unit from the cam shaft 2|. Thereupon. the cotter pin 29 is detached from said cam shaft 2| and, by a suitable wrench, the nut member 26 is retracted to sufficient extent to permit the cam 21 to be rotated on the cam shaft section 2 lb to such position that the high section of said cam 21 assumes substantially its lowermost position to thereby hold the cam follower 34 substantially in its lowermost position whereby the trigger motor spring 45 is compressed to substantially its maximum extent,-this'being necesary, as known in the art, to cause the machine gun to be fired.

Thereupon, the nut member 28 is tightened, the cotter pin, 29ireinserted in the camshaft and the solenoid structure returnedto the position shown in the drawings and fastened to the housing by the described bolts 9a. The teeth of the clutch ring 26 are staggered with respect to the, adjacent sets of clutch teeth and, therefore, the provision of said clutch ring 26 introduces a fineness of adjustment which would not be present were said clutch ring 26 not provided.

During flight of the aircraft and while the machine gun is non-operative, the cam shaft 2| is held by the spring in its extreme position toward the right, Fig. 1, whereby the notched or clutch end of said camshaft 2| is disengaged from'the clutch disk 1 as shown in Fig. 3. Ac cordingly, when the cam shaft 2| is positioned longitudinally as last described, the shaft 6 rotates freely but this rotation is without effect on the cam shaft 2| which remains stationary at this time. 1

When it becomes desirable or necessary to operate the machine gun, the circuit through the solenoid winding is closed by operating a suitable switch, not shown, included inthe circuit of the conductors l9 and 20. When the solenoid winding isthus energized, the associated core member 22 is moved from right to left, Fig. 1, to the position thereof shown to thereby move the cam shaft 2| in the same direction and to effect engagement of the clutch face at the end thereof with the clutch disk 1, the core member 22 remain-. ing stationary, when positioned as last described, during continuous rotation of the cam shaft 2|. By this action, the cam shaft 2| is-connected'to the constantly rotating shaft 6 and is rotated thereby at the same speed as the shaft 6, the cam 21, once for each revolution of said cam shaft 2|, engaging the cam roller 36 tothereby move the cam follower 34 downwardly and effect the firing operation by actuation of the known member'in the trigger motor 44. 7

When operation of the machine gun is to be discontinued, the aforesaid circuit through the solenoid winding is opened whereupon, by action of the spring 25, the cam shaft 2| is moved longitudinally from left to right, Fig. l, to disengage disk I. Thereafter, while the solenoidwinding remains deenergized, the cam shaft 2| remains stationary even though rotation of the shaft 6 continues so long as the aircraft motor continues to operate. i

-During operation of the machine gun, it will be understood that the cam follower 34 reciprocates at high speed. The-cam 21 produces'each down-.

ward stroke of the cam follower 34 and the trigger motor spring 45 effects each return stroke of said cam follower 34. At the top of each return stroke,

the flangedsurface 34c of the cam follower engages the washer 4|with sudden impact and this may, for an instant only, produce slight compression of the spring 40 which, as stated above, is stronger thanthe spring 45. The spring 46, therefore, has the desirable characteristic of absorbing shock from'the cam follower 34. This contributes effectively to smoothness of operation and largely or entirely decreases pounding action of the cam roller.36 on the lowsectionof the cam 21 during cam follower reciprocation.

It is a feature of the invention that, during non-operation of the machine gun, the cam shaft 2| is to be free from any frictional effect imposed thereon by the trigger motor spring 45 acting through the cam follower 34. Thus, during such non-operation of the machine gun, the cam follower 34 is held by the spring 40 in the position shown in Fig. 1 wherein the cam follower roller 36 is indicated as spaced a small or minutedistance, for example, the distance in from the circular surface or low section of the cam 21. Accordingly, when the solenoid winding I2 is energized to initiate operation of the machine gun, the cam 21 moves from. right to left, Fig. 1, free from contact with the roller 36 or any part of the cam follower 34. Therefore, the trigger motorspring 45 producesno friction on the cam shaft 2| at this time. Accordingly, the power .of the solenoid winding I 2. may be low compared with the solenoid power required with prior art machine gun synchronizing devices but, even so, by reason of the described friction-free relation between the cam 21 and the cam follower roller 34, energization of the solenoid winding |2 initiates firing of the machine gun instantly, positively and in a troublefree manner. Further, particularly by reason of the low power required for operating purposes, the mechanism as a whole may be small and compact.

It might be stated that, when the solenoid winding I2 is opened to permit longitudinal movement of the cam shaft 2| from left to right, Fig. 1, under the influence of the spring 25, rotation of the cam shaft 2| would cease in such position that the high section of the cam 21 would be in engagement with the cam roller 36 and, therefore, that the friction-free relation between said cam 21. and the cam follower 34 would not exist. However, this does not happen. Should rotation of the cam shaft 2| tend to cease in such position that the high section of the cam 21 is in engagement with the cam roller 36, an unstable condition would be established between the surface of the cam 21, which, as shown in Fig. 2, is of elliptical configuration, and the adjacent cam roller 36. In actual practice, it has been-demonstrated repeatedly that the cam shaft 2| invariably takes a stationary position wherein the high section of the cam 21 has moved beyond the cam roller 36. Hence, in view of the foregoing, it will be understood that the described longitudinal movement ofthe1 cam shaft 2| from right to left, Fig. .1,

shaft by the trigger motor spring 45.

It is a further feature of the invention that, during operation of the machine gun, the cam shaft 2| is to be momentarily free from friction imposed thereon by the trigger motor spring 45 once during each period that the cam shaft 2| rotates through an angle of 360 degrees. .While the machine gun operates, the highsectionof the cam 21 engages the cam follower roller 36 to move the cam follower 34 downwardly and then upwardly. While these parts are in engagement, the trigger motor spring 45 applies a force to the cam shaft 2| which would impede longitudinal movement thereof should such movement be attempted at this time. However, as the low sectionof the cam 21 comes opposite the roller 36; the cam follower spring control is transferred from the spring 45 to the spring 40 and it is at this time that the friction applied by the cam follower to the cam shaft 2| becomes nil. Therefore, when the solenoid winding I2 is deenergized, the spring 25 effectively moves the cam shaft 2| from left to right, Fig. 1, to disconnect the same from the rotating source of powerproduced by the aircraft engine.

-. In view of the foregoing description, it will readily be understood that, in addition to those mentioned, the control mechanism of my invention-is characterized by many novel and advantageous features. a

As'regards the anti-friction thrust bearings 23 and 24 at opposite, respective ends of the cam shaft 2|, the bearin 24 forms a seat for one end of the spring 25 while the bearing 23 cooperates with the solenoid core 22 to reduce friction when the latter remains stationary inthe position shown in Fig. 1 during operation of the control mechanism.

As discussed above, the cam shaft 2| is free from friction or without load while being moved from right to left, Fig. 1. Therefore, there is little shock or impact when the clutch face of the cam shaft 2! engages the clutch disk 1. a

A major advantage, compared with prior art devices, resides in the fact that the cam shaft rotates only during continuance of the firing operation. This greatly decreases bearing wear as well as wear on the cooperating cam surfaces.

The mehanism of my invention is free from shims, eccentrics and the like as ordinarily used for adjusting purposes in prior art devices. Excepting the adjustment of the operating cam circumferentially of the cam shaft, no other adjustments are required with respect to my novelmechanism which, therefore, is well adapted for installation and care by unskilled labor.

With the parts positioned as shown in Fig. 1, the cam 27, as it rotates, intermittently engages the cam roller 36 in an area of the latter which is spaced equidistantly from the respective sides of said cam roller 36. When the solenoid winding l2 has been deenergized and the spring 25 has moved the cam shaft 2| to its position toward the right, Fig. 1, the cam 2'! is still opposite the cam roller 35 in the sense that it would engage the periphery and not the side of said cam roller 36 should rotation of the cam shaft 2| be initiated at this time. Obviously, the cam shaft 2| should be incapable of moving to such extent toward the right, Fig. 1, that the cam 21 would no longer be opposite the cam roller 36. If the arrangement should be of this character and if the cam shaft 2| should stop in such a position that the cam 21 is disposed downwardly, the ensuing energize.-

is never impeded by friction produced on said camtion of the solenoid would cause the cam 21 to engage the adjacent side face of the cam roller 36.

It'is a feature of theinvention, as hereinbefore pointed out, that the springs 4|] and 45 apply opposite forces to the cam follower 34. In further explanation of this feature of the invention from a practical viewpoint, it is pointed out that the force of the spring is related to the force of the trigger motor spring plus the friction effect produced by the trigger motor. For example, should the friction of thetrigger motor and the force of the trigger motor spring 45 be 500 pounds,.the opposing force of the spring 40 shouldbe somewhat greater, for example, 515 pounds or 525 pounds.

It is a feature of.the invention that a plurality of washers 4| having different thicknesses are provided. Then, having ascertained the combined friction force and spring tension force of the trigger'motor 44, a washer4| is chosen for association with the spring 40 which will cause saidspring 40 to apply an opposing force to the trigger motor somewhat greater than said combined friction force and spring tension force of the trigger motor.

In view of the foregoing, it will be understood that, by selecting the proper washer 4|, the device of my invention can be operated on any load which may be produced by the trigger motor on the cam follower 34 without increase in the load on the solenoid winding or the return spring 25. 7

While the invention has been described with respect to a certain particular preferred example which gives satisfactory results, it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent is:

1. In mechanism of the character described, a cam shaft, a cam thereon, a cam follower having a member adapted to be actuated by said cam, means for biasing said cam follower in one direction whereby said member tends to approach said cam, means stronger than said first named means for biasing said cam follower in reverse direction whereby said member tends to recede from said cam, and means for limiting the effect of said second named biasing means on said cam follower.

2. In mechanism of the character described, a housing, a journalled cam shaft in said housing, a cam on said cam shaft, a cam follower reciprocatory in said housing and having a roller adapted to be actuated by said cam, a spring for biasing said cam follower in one direction whereby said roller tends to approach said cam, a spring stronger than said first spring for biasing said cam follower in reverse direction whereby,

said roller tends to recede from said cam, and means for limiting the effect of said second spring on said cam follower, said second spring serving as a shock absorber during reciprocation of said cam follower.

3. In a mechanism of the kind described, the combination of a shaft mounted for rotation, a cam fast on the shaft, a cam follower encircling the shaft and provided with means at one side of the shaft only engageable by the cam to move the cam follower longitudinally as the cam rotates, a pair of springs acting on the cam follower at the other side of the shaft and tending, respectively, to move the cam follower into and out of engagement with the cam, the spring tending to move the cam follower out of engagement with the cam being the stronger, and means limiting the movement of the cam follower by the stronger spring, whereby the cam follower is free of the low portion of the cam but engageable by the high portion of the cam.

4. In a mechanism of the kind described, the combination of a, shaft mounted for rotation, a cam fast on the shaft, a cam follower encircling the shaft, guides at opposite sides of the shaft in which the cam follower is longitudinally movable, a roller on the cam follower at one side of the shaft engageable by the cam, whereby the latter moves the cam follower as the cam rotates, a pair of springs acting on the cam follower at the other side of the shaft and tending to move the cam follower in opposite directions with the roller, respectively, approaching and receding from the cam, the spring acting on the cam follower to move with the roller receding from the cam being the stronger, and means limiting the movement of the cam follower by the stronger spring,

whereby the roller is kept free of the low portion of the cam and is engageable by the high portion.

VICTOR F. ZAI-IODIAKIN. 

